Overview: WFPC2 Datasets ST-ECF Archive

Wide Field / Planetary Camera 2: dataset description

During the pipeline calibration, datasets consisting of

a Standard Header Packet (SH),
a Science Image (D0),
a Science Image Data Quality file (DQF),
an Extracted Engineering Data file (EED)
an Extracted Engineering Data Quality file (Q1)

are created for the Wide Field / Planetary Camera 2.

These data sets are used as input to the standard calibration program, CALWP2, which produces four types of calibrated science files:

a calibrated science image image (C0)
a calibrated science image data quality file (C1)
a group parameter file (CGR, DGR)
a calibrated science image histograms file (C2)
a saturated and missing pixels file (C3)

CALWP2 performs a standard sequence of processing steps on individual WF/PC-II camera observations designed to remove most of the known instrumental signature. CALWP2 does the AtoD fixup, determines and removes the global bias level, subtracts bias, pre-flash, dark, and superpurge frames (after appropriate scaling), and applies the flat field frame.

All files for a particular observation have the same root file name;
the type of data in each file is identified by its extension.

The format of all retrieved files from the ST-ECF archive is FITS.

File Type Short Name File Extension Short Description

Standard Header Packet SHP shf.fits Telemetry values and spacecraft operation data. This file is not currently used by CALWP2, but it is part of the standard WF/PC-II dataset.

Science Image file D0 d0f.fits It contains the WF/PC-II image data with the readout from each CCD detector in each group. Hence from 1 to 4 groups may be present. Keywords in the header are used to select the various processing steps and to specify the names of the necessary reference files.

Science Data Quality file DQF q0f.fits The DQF must consist of short integers and have the same dimensions and number of groups as the Science Image file. Each pixel indicates the quality of the corresponding pixel in the Science Image file. Zero valued pixels indicate "good" pixels in the Science Image file and nonzero valued pixels flag various problems or potential problems with their corresponding pixels.

Extracted Engineering Data file EED x0f.fits It contains the two "engineering" column and, for FULL mode, the 12 columns of overclocked pixels. It has the same number of groups as the Science Image file.

Extracted Engineering Data Quality file Q1 q1f.fits The EED quality file must consist of short integers and have the same dimensions and number of groups as the EED file. Each pixel indicates the quality of the corresponding pixel in the EED file. Zero valued pixels are "good" pixels in the EED file and nonzero valued pixels flag various problems or potential problems with their corresponding pixels.

Calibrated Science Image file C0 c0.fits It is in REAL format (although an option is available to provide FITS-like scaling to SHORT or LONG integers). Extreme values resulting from input data values outside of the range of the WF/PC-II AtoD converter (0 to 4095) are edited to limit the range of values in the output image. These pixels are set to the value of the keyword RSDPFILL and flagged in the DQF.

Calibrated Science Image Data Quality file C1 c1.fits The DQF for the Calibrated Science Image file follows the same conventions as the Science Image Data Quality file. This contains the result of bitwise ORing, the input DQF, and all DQFs associated with reference files used in the processing of the Science Image file.

Group Parameter file CGR, DGR cgr.fits, dgr.fits This file lists the group parameters and associated values in the calibrated science image. Each group parameter name has the string "_1", "_2", "_3", or "_4" appended to it, depending on whether it refers to group 1,2,3, or 4 respectively, of the calibrated (output) science image. Each group parameter string so modified is left-justified in a 10-column field, followed by the "=" sign and a blank, followed by the value of the parameter for that group. This output file is identified by the extension CGR, and is used primarily by the Data Archiving group. A similar file, with the extension DGR, is created during generic conversion containing the group parameters in the raw (i.e., uncalibrated) Science Image file.

Calibrated Science Image Histograms file C2 c2.fits This file consists of three rows and the same number of groups as the Science Image file. The first row contains the histogram of the pixel values in the Science Image file.
The second row contains the histogram following the AtoD correction step.
The third row contains the histogram of the Calibrated Science Iamge file values.
The creation of this file is controlled by the keyword DOHISTOS in the input science image header and includes only thos values flagged as good in the DQF.

Saturated and Missing Pixels file C3 c3.fits The map of saturated and missing pixels is a DQF generated primarily as an input file for the WF/PC-II Stage II Pipeline. The creation of this file is controlled by the keyword DOSATMAP in the input science image header.

File Type	Short Name	File Extension	Short Description
Standard Header Packet	SHP	shf.fits	Telemetry values and spacecraft operation data. This file is not currently used by CALWP2, but it is part of the standard WF/PC-II dataset.
Science Image file	D0	d0f.fits	It contains the WF/PC-II image data with the readout from each CCD detector in each group. Hence from 1 to 4 groups may be present. Keywords in the header are used to select the various processing steps and to specify the names of the necessary reference files.
Science Data Quality file	DQF	q0f.fits	The DQF must consist of short integers and have the same dimensions and number of groups as the Science Image file. Each pixel indicates the quality of the corresponding pixel in the Science Image file. Zero valued pixels indicate "good" pixels in the Science Image file and nonzero valued pixels flag various problems or potential problems with their corresponding pixels.
Extracted Engineering Data file	EED	x0f.fits	It contains the two "engineering" column and, for FULL mode, the 12 columns of overclocked pixels. It has the same number of groups as the Science Image file.
Extracted Engineering Data Quality file	Q1	q1f.fits	The EED quality file must consist of short integers and have the same dimensions and number of groups as the EED file. Each pixel indicates the quality of the corresponding pixel in the EED file. Zero valued pixels are "good" pixels in the EED file and nonzero valued pixels flag various problems or potential problems with their corresponding pixels.
Calibrated Science Image file	C0	c0.fits	It is in REAL format (although an option is available to provide FITS-like scaling to SHORT or LONG integers). Extreme values resulting from input data values outside of the range of the WF/PC-II AtoD converter (0 to 4095) are edited to limit the range of values in the output image. These pixels are set to the value of the keyword RSDPFILL and flagged in the DQF.
Calibrated Science Image Data Quality file	C1	c1.fits	The DQF for the Calibrated Science Image file follows the same conventions as the Science Image Data Quality file. This contains the result of bitwise ORing, the input DQF, and all DQFs associated with reference files used in the processing of the Science Image file.
Group Parameter file	CGR, DGR	cgr.fits, dgr.fits	This file lists the group parameters and associated values in the calibrated science image. Each group parameter name has the string "_1", "_2", "_3", or "_4" appended to it, depending on whether it refers to group 1,2,3, or 4 respectively, of the calibrated (output) science image. Each group parameter string so modified is left-justified in a 10-column field, followed by the "=" sign and a blank, followed by the value of the parameter for that group. This output file is identified by the extension CGR, and is used primarily by the Data Archiving group. A similar file, with the extension DGR, is created during generic conversion containing the group parameters in the raw (i.e., uncalibrated) Science Image file.
Calibrated Science Image Histograms file	C2	c2.fits	This file consists of three rows and the same number of groups as the Science Image file. The first row contains the histogram of the pixel values in the Science Image file. The second row contains the histogram following the AtoD correction step. The third row contains the histogram of the Calibrated Science Iamge file values. The creation of this file is controlled by the keyword DOHISTOS in the input science image header and includes only thos values flagged as good in the DQF.
Saturated and Missing Pixels file	C3	c3.fits	The map of saturated and missing pixels is a DQF generated primarily as an input file for the WF/PC-II Stage II Pipeline. The creation of this file is controlled by the keyword DOSATMAP in the input science image header.

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Last update: Jul 31, 1996